Collapsible support frames for receptacles falling within this category comprise a frame of generally rectilinear configuration including front, rear and side portions, the front, rear and side portions consisting of means to support the frame structure so as to present the disposable receptacle opening upwardly when same engages the support frame.
One example of an early support frame for a receptacle is that found in U.S. Pat. No. 3,227,137 wherein a liner for a sanitary container or commode is disclosed such that the liner is fabricated from polyethylene and is shaped so as to be easily fitted into a container of upright square or rectangular configuration.
The liner is fabricated from a long tubular section of thermoplastic material folded inwardly at opposite sides for approximately one-third of the total diameter of the tube to present folds on either sides.
After the folds have been made the tubular arrangement is compressed and a heat seam is made substantially along the bottom edge thereof.
As the front and rear walls are moved apart exposing the heat sealed seam triangular configurations are produced which result in further folds directed towards the bottom of the liner acting as reinforcements.
The sides of the liner extend vertically so as to extend beyond the side walls of the container and are folded thereover. The walls of the commode give support to the liner.
Another prior alternative is the pet commode disclosed in U.S. Pat. No. 3,358,647 which is particularly directed towards a foldable and disposable receptacle.
The tray like receptacle comprises a tubular frame with a removable cover for placement with the frame upon the floor or other flat supporting surface. Further, an envelope or bag like cover of polyethalene is selected to be of a size so as to loosely enclose the frame. When such bag-like cover is fitted with the frame the upper layer will be supported and lie flat on the lower layer to form a double thickness dish-like container having a depth of the order of the diameter of the component rods of the frame.
Still another embodiment of a support frame for a receptacle demonstrating the trend of development in this field is that disclosed by U.S. Pat. No. 3,416,495 in which a litter box or commode is defined by upstanding walls of rectilinear configuration in plan from which extends an integral flexible sheet. Such commode or container is adapted to receive a paper liner which corners extend over the corners of the frame and are held down by elastic bands anchored over upwardly projecting knobs formed integrally with the framework at the corners thereof.
This patent reveals the use of extensible anchoring elements, preferabley elastic bands, for securing a liner to the supporting frame.
Finally, another prior alternative is revealed by Canadian Pat. No. 923,093 in which a collapsible unit is defined by a substantially rectangular frame and a bag of flexible material which has a bottom panel, two pairs of opposed side panels and an open upper face of substantially the same size and shape as the rectangular frame.
Located at the side panels are at least two extending members having substantially the same size and shape which swing outwardly to establish the tautness of the bag together with a board which is stiff when disposed between the extending members urging them against adjacent side panels.